Dynamically updating map projections

ABSTRACT

Embodiments of the invention may provide the ability to dynamically create and update map projections to reduce the spatial distortion in a desirable way for a specific map view. For example, as a map view is changed, a new central meridian may be selected and a new map projection may be created based on the selected central meridian. Dynamically updating map projections so that all map layers are correctly representing the most important spatial attributes for the given situation may enable a map analyst to correctly interpret the maps being viewed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 12/981,020, filed Dec. 29, 2010, the contents ofwhich is incorporated herein by reference in its entirety.

BACKGROUND

The present invention relates to displaying maps, and more particularlyto displaying dynamically updated map projections.

It is well known that representing a spherical surface (globe) onto aflat surface (computer screen or paper) results in the distortion of oneor more spatial properties. A map projection works by a set of ruleswhich dictate where locations on a globe (earth) should be located on aflat surface. While many map projections have been created, they alldistort one or more of the following four spatial properties: shape,area, distance, direction. Such spatial distortion is greater in someparts of the projection than in other parts.

BRIEF SUMMARY

In one embodiment of the invention, a method for displaying mapprojections comprises, in response to one or more desired changes to oneor more aspects of a map view, selecting a central meridian for thedesired changed map view and creating a new map projection based on theselected central meridian to reduce distortion of one or more spatialproperties in the desired changed map view. The one or more desiredchanges to one or more aspects of a map view may comprise one or moredesired changes to a viewable area of the map. The one or more desiredchanges to a viewable area of the map may be selected using one or moreof scroll, zoom, or pan controls.

The map view may comprise a line segment. If the line segment issubstantially straight then the selected central meridian corresponds tothe line segment. If the line segment is not substantially straight thenthe selected central meridian corresponds to a line that is fit to theline segment.

The map view may comprise one or more landmarks, and the selectedcentral meridian may correspond to a line intersecting one or more ofthe landmarks. The map view may comprise a plurality of data points, andthe selected central meridian may comprise a line of central tendency ofthe plurality of data points. The one or more desired changes to one ormore aspects of a map view may comprise one or more desired changes to aselection of data from a dataset.

In addition to the method of displaying map projections, as describedabove, other aspects of the present invention are directed tocorresponding systems and computer program products for displaying mapprojections.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawings, which are not necessarily drawn toscale, and wherein:

FIGS. 1-6 are map projections illustrating the operation of dynamicallydisplaying map projections according to various aspects of the presentinvention;

FIG. 7 is a schematic block diagram of a computer network in whichembodiments of the present invention may operate; and

FIG. 8 is a schematic block diagram of a computer in the network of FIG.7.

DETAILED DESCRIPTION

Embodiments of the invention may provide the ability to dynamicallycreate and update map projections to reduce the spatial distortion in adesirable way for a specific map view. For example, when working with aTransverse Mercator projection, a central meridian may be selected toreduce distance along the line segment of most interest for a specificmap view. As a map view is changed (such as, for example, in response toa user selection as discussed in more detail below), a new centralmeridian may be selected and a new map projection may be created basedon the selected central meridian. Dynamically updating map projectionsso that all map layers are correctly representing the most importantspatial attributes for the given situation may enable a map analyst tocorrectly interpret the maps being viewed.

The specific type of map projection that may be created may vary, suchas according to the spatial property which is desired to be lessdistorted. For example, if it is desired to accurately display distancealong the central meridian, it may be desirable to create a TransverseMercator projection. However, any known type of projection may becreated using embodiments of the invention. For example, an Albers EqualArea Conic projection may be dynamically created using embodiments ofthe present invention. The Albers Equal Area Conic projection preservesangles between meridians and parallels. The Albers Equal Area Conicprojection attempts to minimize distortion for both shape and linearscale, but neither is truly correct. Another projection that may bedynamically created using embodiments of the present invention is theChamberlin Trimetric projection which is used by the National GeographicSociety for mapping most continents. The Chamberlin Trimetric projectionis a three-point equidistant projection, which preserves the distancebetween three reference points relative to any other point. Anotherprojection that may be dynamically created using embodiments of thepresent invention would be a conformal map projection which is used formaps where the measurement of angles is important, such as aeronauticalcharts and topographic maps. Hundreds of projections have been developedin order to accurately represent a particular map element or to bestsuit a particular type of map or task.

The central meridian that is selected may be chosen to reduce thespatial distortion in a desirable way for a specific map view. Forexample, one type of map might illustrate specific information as one ormore (straight or non-straight) lines. Such information may includeroadways, rivers, travel directions (e.g., turn-by-turn drivingdirections, planned aircraft flight routes, or planned shipping routes),train tracks, pipelines, communication cables, power lines, etc. Forsuch a map, the central meridian may be selected to correspond to theone or more lines (as discussed in more detail below).

A different type of map might illustrate specific information as one ormore points. For example, the points might represent geographiclocations (e.g., places of interest or points along turn-by-turn drivingdirections), or may represent data points (e.g., crime data, populationdemographics, etc.) For such a map, the central meridian may be selectedto correspond to one or more of the points (as discussed in more detailbelow).

A new central meridian may be selected and a new map projection createdusing the new central meridian as needed in order to display a map viewto a user that has reduced spatial distortion. For example, a newcentral meridian may be selected and a new map projection created usingthe new central meridian in response to one or more desired changes toone or more aspects of a map view. Changes to a map view may comprise,for example, changes to a viewable area of the map. Such changes to theviewable area occur in response to, for example, a user scrolling a mapview, zooming in or out, or panning Such viewing controls are well knownin the art. Changes to a map view may also comprise, for example,changing one or more filter selections which in turn change the datapoints displayed on a map. Such a change to a map view is illustrated inFIGS. 4 and 5 and discussed in more detail below.

Referring now to FIG. 1, map view 10 shows the state of Alaska and theTrans Alaska Pipeline 12. Pumping stations 14 along the pipeline arealso shown. Map view 10 comprises a map projection that uses line 16 asthe central meridian. Map view 10 may be, for example, a TransverseMercator projection. Central meridian 16 may be selected to correspondto the illustrated portion of the pipeline (which in FIG. 1 is theentire pipeline). To select a central meridian that corresponds to a mapfeature that appears as a line (such as the pipeline of FIG. 1), if theline is substantially straight then the selected central meridiancorresponds to the line, and if the line is not substantially straightthen the selected central meridian corresponds to a line that is fit tothe non-straight line using any suitable line-fitting method. Since thepipeline of FIG. 1 is not a straight line, a straight line 16 is fit tothe non-straight line 12 of the pipeline (using any suitable linefitting technique) and the straight line 16 is used as the centralmeridian. If the illustrated portion of the pipeline were asubstantially straight line, the line illustrating the pipeline could beused as the central meridian.

A user viewing map view 10 of FIG. 1 might desire to zoom in to view aportion of the pipeline in more detail, thereby changing the map view asthe user zooms in. Embodiments of the invention may select a new centralmeridian and create a new map projection using the new central meridianto reduce the spatial distortion near the portion of the pipeline in thezoomed-in view. FIG. 2 illustrates how different central meridians maybe selected when different portions of the pipeline are zoomed in to.Block 20 of FIG. 2a illustrates how a portion of the pipeline frompumping station 1 to pumping station 5 might be selected to zoom in to.Similarly, block 30 in FIG. 2a illustrates how a portion of the pipelinefrom pumping station 6 to pumping station 9 might be selected to zoom into. The portions encompassed in blocks 20 and 30 would be selected forzoom using any suitable technique.

Until the map view is changed by zooming in to block 20 or block 30, themap view of FIG. 2a is the same as that of FIG. 1a and would have thesame central meridian (line 16). When, for example, a user selects block20 to zoom in, the map view would change accordingly to that illustratedin FIG. 2b . In accordance with embodiments of the invention, a newcentral meridian may be selected for the map view of FIG. 2b tocorrespond to the portion of the pipeline that is shown in FIG. 2b(i.e., pumping station 1 to pumping station 5). Since that portion ofthe pipeline is not a straight line, the central meridian would likelycomprise a straight line 26 that has been fit to the pipeline. Theprojection used for the map view of FIG. 2b would be dynamically changedto use line 26 as the central meridian. As such, the map projection ofFIG. 2b would have a central meridian that corresponds to theillustrated portion of the pipeline and therefore the illustratedportion of the pipeline in FIG. 2b will have less spatial distortionthan would otherwise be if the map projection had not been dynamicallyupdated in accordance with embodiments of the invention.

Similarly, when a user selects block 30 to zoom in, the map view wouldchange accordingly to that illustrated in FIG. 2c . In accordance withembodiments of the invention, a new central meridian may be selected forthe map view of FIG. 2c to correspond to the portion of the pipelinethat is shown in FIG. 2c (i.e., pumping station 6 to pumping station 9).Since that portion of the pipeline is not a straight line, the centralmeridian would likely comprise a straight line 36 that has been fit tothe pipeline. The projection used for the map view of FIG. 2c would bedynamically changed to use line 36 as the central meridian. As such, themap projection of FIG. 2c would have a central meridian that correspondsto the illustrated portion of the pipeline and therefore the illustratedportion of the pipeline in FIG. 2c will have less spatial distortionthan would otherwise be if the map projection had not been dynamicallyupdated in accordance with embodiments of the invention.

A user viewing zoomed-in map view 20 of FIG. 2b might desire to scrolldown to view the rest of the pipeline at that zoom level, therebychanging the map view with each scroll increment as the user scrollsdown. Embodiments of the invention may select a new central meridian andcreate a new map projection using the new central meridian to reduce thespatial distortion near the portion of the pipeline viewable in eachcurrent scroll window. FIG. 3 illustrates how different centralmeridians may be selected when different portions of the pipeline arescrolled to. FIGS. 3a, 3b and 3c each illustrate a different portion ofthe pipeline as a user scrolls down. FIG. 3a illustrates the pipelinefrom pumping station 1 to pumping station 4; FIG. 3b illustrates thepipeline from pumping station 5 to pumping station 9; and FIG. 3cillustrates the pipeline from pumping station 8 to pumping station 12.In each discrete map view which is shown as a user scrolls, a newcentral meridian may be selected and a new map projection created usingthe new central meridian dynamically for each map view. The map viewillustrated in FIG. 3a would comprise a map projection created usingline 46 a as central meridian. The map view illustrated in FIG. 3b wouldcomprise a map projection created using line 46 b as central meridian.The map view illustrated in FIG. 3c would comprise a map projectioncreated using line 46 c as central meridian. As such, the illustratedportions of the pipeline in FIGS. 3a, 3b and 3c will have less spatialdistortion than would otherwise be if the map projection had not beendynamically updated in accordance with embodiments of the invention.

As discussed above, a different type of map might illustrate specificinformation as one or more points, such as data points. For such a map,the central meridian may be selected to correspond to one or more of thepoints. For example, the selected central meridian might correspond to aline of central tendency of a plurality of data points. Alternatively,any desired alternative technique for fitting a straight line to pointsmay be used. FIGS. 4-6 illustrate such a type of map, with dynamicallyselected central meridians and dynamically created map projections inaccordance with embodiments of the invention. FIGS. 4-6 couldillustrate, for example, crime statistics where each data point 52represents a recorded crime at a specific geographic location. Sliderbars (or any other suitable selection mechanism) could be used to enablea user to filter data from a dataset and thereby control what and howmuch data is displayed. For example, slider bars 54 include selectionsfor “income range,” “date range,” and “zoom.” As one or more of theseslider bars are changed by a user, the map view (and specifically thedata points displayed) change accordingly. In accordance withembodiments of the invention, as the map view changes in response tochanges to the slider bars, a new central meridian is selected and a newmap projection is created using the new central meridian.

FIG. 4 illustrates a plurality of data points 52 based on the settingsof slider bars 54. A central meridian 56 may be selected based on thesedata points. For example, central meridian 56 may correspond to a lineof central tendency of the data points. Alternatively, any desiredalternative technique for fitting a straight line to points may be used.The map projection of FIG. 4 would use central meridian 56.

FIG. 5 illustrates a plurality of data points 62 based on the settingsof slider bars 64. The zoom slider bar of FIG. 5 has been changed (suchas by a user) to increase the zoom level. As such, fewer data points arevisible in FIG. 5 than in FIG. 4. In accordance with embodiments of theinvention, a new central meridian 66 is dynamically selected based onthe data points that are visible in FIG. 5 and a new map projection isdynamically created based on the new central meridian. As in FIG. 4,central meridian 66 of FIG. 5 may correspond to a line of centraltendency of the data points, or any desired alternative technique forfitting a straight line to points may be used.

FIG. 6 illustrates a plurality of data points 72 based on the settingsof slider bars 74. The zoom slider bar of FIG. 6 has been changed (suchas by a user) to decrease the income range and increase the date range.In this illustration, these changes resulted in fewer data points beingvisible in FIG. 6 than in FIG. 4. In accordance with embodiments of theinvention, a new central meridian 76 is dynamically selected based onthe data points that are visible in FIG. 6 and a new map projection isdynamically created based on the new central meridian. As in FIG. 4,central meridian 76 of FIG. 6 may correspond to a line of centraltendency of the data points, or any desired alternative technique forfitting a straight line to points may be used.

Embodiments of the invention may dynamically select a central meridianbased on heuristic points of value. The map projection could becontinuously and dynamically altered to a human recognizable centralmeridian. For example, embodiments of the invention may be used when amap view comprises one or more landmarks, such that the dynamicallyselected central meridian corresponds to a line intersecting one or moreof the landmarks or other recognizable artifact. Such an embodimentreduces spatial distortion for human meaningful artifacts by “pushing”spatial distortion to the “less meaningful” areas of the map projection.

Embodiments of the invention may dynamically select a central meridianand dynamically create a map projection using the selected centralmeridian for each trip segment of a mapped journey. Such a journey maybe, for example, by car (in which case each trip segment may correspondto a road on which the car is to be driven, in accordance with“turn-by-turn” directions) or by airplane (in which case each tripsegment may correspond to a flight “leg”). By dynamically changing the“central meridian.” for each turn in a trip, the distortion of distancefor that segment of the trip is eliminated.

As an example, consider travel from point A to point D, with midpoints Band C along the route. Such travel could comprise, for example, flightsfrom Charlottesville, Va. airport (CLT) to Washington Dulles airport(IAD), from IAD to Los Angeles airport (LAX), and from LAX to Honoluluairport (HNL). As each segment of that trip is to be displayed, a newmap projection for each trip segment is dynamically created using acentral meridian that corresponds to the line representing the tripsegment. (As discussed above, if the trip segment line is notsubstantially straight then the central meridian may need to be “fit” tothe trip segment line.) So for a trip going from point A to point B topoint C to point D, three map projections may be dynamically created todisplay each trip segment. The line representing trip segment AB (or aline fit to that line) would be the central meridian for the first mapprojection. The line representing trip segment BC (or a line fit to thatline) would be the central meridian for the second map projection. Theline representing trip segment CD (or a line fit to that line) would bethe central meridian for the third map projection.

Further embodiments of the invention may dynamically select a centralmeridian and dynamically create a map projection using the selectedcentral meridian when a map view is to be changed according to task tobe performed (e.g., comparing land parcel sizes versus analyzing crimedata depicted as point symbols). Embodiments of the invention maydynamically select a central meridian and dynamically create a mapprojection using the selected central meridian when a map view is to bechanged in any desired way.

FIG. 7 is a schematic block diagram of a computer network in whichembodiments of the present invention may operate. Computers 82 andserver 84 provide processing, storage, and input/output devicesexecuting application programs and the like. Computers 82 may be linkedover communication link 86 through communications network 80 to eachother and to other computing devices, including server 84.Communications network 80 can be part of the Internet, a worldwidecollection of computers, networks, and gateways that currently use theTCP/IP suite of protocols to communicate with one another. The Internetprovides a backbone of high-speed data communication lines between majornodes or host computers, consisting of thousands of commercial,government, educational, and other computer networks, that route dataand messages. However, computers 82 and server 84 may be linked over anysuitable communication network. In the system of FIG. 7, computers 82may be running Web browsers used for accessing and viewing mappingapplications, such as may be hosted on server 84.

In addition to the client-server arrangement of FIG. 7, embodiments ofthe invention may operate in any client-server arrangement or in anynetworked arrangement in which display elements, data, and/or otherinformation are sent from a source to a recipient. For example,embodiments of the invention may operate in a mobile communications/dataarchitecture (such as a mobile telecommunications network adhering tothe International Mobile Telecommunications-2000 (also termed 3G)standards), in which a mobile telecommunications device (e.g.,cell/mobile telephone) is the recipient.

FIG. 8 is a diagram of the internal structure of a computer (e.g.,computers 82 or servers 84) in the computer network of FIG. 7. Eachcomputer typically contains system bus 98, where a bus is a set ofhardware lines used for data transfer among the components of acomputer. Bus 98 is essentially a shared conduit that connects differentelements of a computer system (e.g., processor, disk storage, memory,input/output ports, network ports, etc.) that enables the transfer ofinformation between the elements. Attached to system bus 98 is I/Odevice interface 100 for connecting various input and output devices(e.g., displays 96, printers, speakers, etc.) to the computer. Networkinterface 104 allows the computer to connect to various other devicesattached to a network (e.g., network 80 of FIG. 7). Memory 90 providesvolatile storage for computer software instructions 91 and data 93 usedto implement an embodiment of the present invention. Disk storage 95provides non-volatile storage for computer software instructions 92 anddata 94 used to implement an embodiment of the present invention.Central processor unit 102 is also attached to system bus 98 andprovides for the execution of computer instructions.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, or store a programfor use by or in connection with an instruction execution system,apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described below with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

“Computer” or “computing device” broadly refers to any kind of devicewhich receives input data, processes that data through computerinstructions in a program, and generates output data. Such computer canbe a hand-held device, laptop or notebook computer, desktop computer,minicomputer, mainframe, server, cell phone, personal digital assistant,other device, or any combination thereof.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present invention has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

That which is claimed:
 1. A method for displaying map projections, themethod being implemented by a computer, the method comprising: inresponse to one or more desired changes to one or more aspects of a mapview, selecting a central meridian for the desired changed map view; andcreating a new map projection based on the selected central meridian,wherein the new map projection has one or more differences in distortionfrom a prior map projection based on a prior central meridian.
 2. Themethod of claim 1, wherein the one or more desired changes to one ormore aspects of a map view comprises one or more desired changes to aviewable area of the map.
 3. The method of claim 2, wherein one or moredesired changes to a viewable area of the map are selected using one ormore of scroll, zoom, or pan controls.
 4. The method of claim 2, whereinthe map view comprises a line segment, wherein if the line segment issubstantially straight then the selected central meridian corresponds tothe line segment, and wherein in the line segment is not substantiallystraight then the selected central meridian corresponds to a line thatis fit to the line segment.
 5. The method of claim 2, wherein the mapview comprises one or more landmarks, and wherein the selected centralmeridian corresponds to a line intersecting one or more of thelandmarks.
 6. The method of claim 1, wherein the map view comprises aplurality of data points and wherein the selected central meridiancomprises a line of central tendency of the plurality of data points. 7.The method of claim 6, wherein the one or more desired changes to one ormore aspects of a map view comprises one or more desired changes to aselection of data from a dataset.